Classifications

• • D—TEXTILES; PAPER
  • D02—YARNS; MECHANICAL FINISHING OF YARNS OR ROPES; WARPING OR BEAMING
  • D02J—FINISHING OR DRESSING OF FILAMENTS, YARNS, THREADS, CORDS, ROPES OR THE LIKE
  • D02J1/00—Modifying the structure or properties resulting from a particular structure; Modifying, retaining, or restoring the physical form or cross-sectional shape, e.g. by use of dies or squeeze rollers
  • D02J1/22—Stretching or tensioning, shrinking or relaxing, e.g. by use of overfeed and underfeed apparatus, or preventing stretch
  • D02J1/221—Preliminary treatments
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B60—VEHICLES IN GENERAL
  • B60C—VEHICLE TYRES; TYRE INFLATION; TYRE CHANGING; CONNECTING VALVES TO INFLATABLE ELASTIC BODIES IN GENERAL; DEVICES OR ARRANGEMENTS RELATED TO TYRES
  • B60C9/00—Reinforcements or ply arrangement of pneumatic tyres
  • B60C9/0042—Reinforcements made of synthetic materials
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F1/00—General methods for the manufacture of artificial filaments or the like
  • D01F1/02—Addition of substances to the spinning solution or to the melt
  • D01F1/10—Other agents for modifying properties
• • D—TEXTILES; PAPER
  • D01—NATURAL OR MAN-MADE THREADS OR FIBRES; SPINNING
  • D01F—CHEMICAL FEATURES IN THE MANUFACTURE OF ARTIFICIAL FILAMENTS, THREADS, FIBRES, BRISTLES OR RIBBONS; APPARATUS SPECIALLY ADAPTED FOR THE MANUFACTURE OF CARBON FILAMENTS
  • D01F6/00—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof
  • D01F6/58—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products
  • D01F6/62—Monocomponent artificial filaments or the like of synthetic polymers; Manufacture thereof from homopolycondensation products from polyesters
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M7/00—Treating fibres, threads, yarns, fabrics, or fibrous goods made of other substances with subsequent freeing of the treated goods from the treating medium, e.g. swelling, e.g. polyolefins
• • D—TEXTILES; PAPER
  • D06—TREATMENT OF TEXTILES OR THE LIKE; LAUNDERING; FLEXIBLE MATERIALS NOT OTHERWISE PROVIDED FOR
  • D06M—TREATMENT, NOT PROVIDED FOR ELSEWHERE IN CLASS D06, OF FIBRES, THREADS, YARNS, FABRICS, FEATHERS OR FIBROUS GOODS MADE FROM SUCH MATERIALS
  • D06M2200/00—Functionality of the treatment composition and/or properties imparted to the textile material
  • D06M2200/40—Reduced friction resistance, lubricant properties; Sizing compositions

Definitions

• This invention relates to polyester reinforcement for rubber articles, such as tires, belts, hose, and the like. More particularly, it relates to a treatment for polyester fibers to improve the adhesion thereof to rubber and to improve the fatigue resistance thereof in use in the rubber articles wherein they are to be used as reinforcement.
• this mixture of aromatic isocyanates greatly improve the dry heat drawability of polyester filaments treated therewith so that this generally preferred drawing process can be utilized and the unexpectedly improved fatigue resistance of the end product can be achieved, but we have discovered that higher adhesive strengths are realized than when the difunctional aromatic isocyanate is used alone. Also, use of this mixture of aromatic isocyanates yields products of reduced stiffness which makes the products easier to utilize in the embedding process (e.g. "tire-building" process) and avoids premature fatigue failure of stiffer cords breaking the adhesive bond to the rubber and abrading each other.
• synthetic linear condensation polyester refers to a linear polymer comprised of recurring structural units containing, as an integral part of the polymer chain, recurring carbonyloxy groups ##STR1## and having a relative viscosity of at least about 25 in a solution of 11 g. of polymer in 100 ml. of a mixed solvent composed of 10 parts by weight of phenol and 7 parts by weight of trichlorophenol.
• the polyester is one of the polymethylene terephthalates described in U.S. Pat. Nos. 2,465,319; 3,051,212; and 3,216,187. Polyethylene terephthalate is the especially preferred commercial polyester at present.
• the process of manufacturing filaments of polyester for use as reinforcement for rubber articles it is usual to include at some point in the process, at least one drawing step wherein the filaments are stretched or elongated to orient the molecules therein thereby increasing the strength of such filaments.
• drawing step or steps serve to elongate the filaments to about 4 to 7 times their undrawn length.
• Numerous means are known for accomplishing such drawing step or steps which can be used in conjunction with the present invention, although it is generally preferred to utilize those means wherein the filaments are heated in air in contact with a heated surface such as heated rolls, heated platens, heated draw pins, etc. which may be heated internally (as by internal electric heaters) or externally (as by radiant heaters) or combinations thereof.
• a resorcinol-formaldehyde-latex dip (commonly termed an RFL dip) to such filaments prior to embedding them in the rubber or to use certain rubber adhesion-promoting additives, such as a combination of a formaldehyde-donor (e.g. trimethylolnitromethane, trimethylolacetoaldehyde, hexamethylenetetramine, paraformaldehyde, or hexamethoxymethylmelamine) and a polyhydroxyphenol (e.g. resorcinol or phloroglucinol) with or without hydrated silica.
• a formaldehyde-donor e.g. trimethylolnitromethane, trimethylolacetoaldehyde, hexamethylenetetramine, paraformaldehyde, or hexamethoxymethylmelamine
• a polyhydroxyphenol e.g. resorcinol or phloroglu
• polyester filaments have been treated with certain adhesion promotors, such as polyepoxides, isocyanates, ethyleneureas, etc.
• adhesion promotors such as polyepoxides, isocyanates, ethyleneureas, etc.
• the present invention is an improvement on this technology when aromatic isocyanates are used as the pretreatment to enhance the adhesion of polyester filaments to rubber whether or not an RFL or other elastomer-containing dip or rubber adhesion-promoting additives are used.
• the present invention has for its objects providing an operable dry heat drawing process for stretching isocyanate-pretreated polyester filaments, and producing polyester reinforcement for rubber articles giving improved adhesion to rubber, improved fatigue resistance, and reduced stiffness. Other objects will appear as the more detailed description and exemplification proceeds.
• the isocyanate applied to the polyester filaments is a mixture of 50 to 90% di-functional aromatic isocyanates and the remainder higher than di-functional aromatic isocyanates.
• such mixture of isocyanates should be applied to the polyester filaments as a solution in a chlorinated hydrocarbon solvent.
• the di-functional aromatic isocyanates useful for this invention are those aromatic isocyanates containing exactly two isocyanate groups per molecule, such as methylene-bis(4-phenylisocyanate) dimer and TDI-dimer (wherein one isocyanate from each of two MDI or MDI; toluene-diisocyanate or TDI; MDI-dimer or TDI units react to form an ##STR2## bridge); ethylene-bis-(N-3-isocyanato-4-methylphenylurethane; phenylene-diisocyanate; naphthalene-diisocyanate; 3,3'-dimethyl or dimethoxy-4,4'-bis-phenylene-diisocyanate; 4,4'-bis(2-methyl or methoxyisocyanatophenyl)methane; chlorobenzene diisocyanate; nitrobenzene diisocyanate; xylylene-diis
• the higher than di-functional aromatic isocyanates useful for this invention are those aromatic isocyanates containing more than two (namely, three or more) isocyanate groups per molecule, such as polymethylene-polyphenylisocyanate or PAPI [which includes dimethylene-tris(phenylisocyanate) as the trimer, trimethylene-tetrakis(phenylisocyanate) as the tetramer, etc.]; toluene triisocyanate; triphenylmethane triisocyanate; MDI-trimer and TDI-trimer (wherein one isocyanate from each of three MDI or TDI units react to form an isocyanurate bridge); etc., and mixtures thereof.
• PAPI polymethylene-polyphenylisocyanate
• PAPI which includes dimethylene-tris(phenylisocyanate) as the trimer, trimethylene-tetrakis(phenylisocyanate) as the tetramer, etc
• the mixture of aromatic isocyanates may be applied to the polyester filaments as a concentrated solution in an inert solvent such as a hydrocarbon, an ether, a ketone, or an ester, although a chlorinated hydrocarbon solvent is preferred.
• an inert solvent such as a hydrocarbon, an ether, a ketone, or an ester
• chlorinated hydrocarbon solvent is preferred.
• such solvents are toluene, xylene, bis-(2-methoxy-ethyl)ether, 3-pentanone, methyl ethyl ketone, ethyl acetate.
• Illustrative of the chlorinated hydrocarbon solvents which are preferred are chlorobenzene, dichloroethylene, trichloroethylene, tetrachloroethane, and perchloroethylene.
• the amount of this mixture of aromatic isocyanates applied to the polyester filaments results in a coating of 0.05 to 5% on weight of fiber.
• the isocyanate mixture contain 50 to 90% di-functional aromatic isocyanates and the remainder higher than di-functional aromatic isocyanates. If the isocyanate used is all di-functional aromatic isocyanate, the adhesive strength is significantly lower than when the mixture of this invention is used. If the isocyanate mixture contains too much higher than di-functional aromatic isocyanate and too little di-functional isocyanate, the drawability of the polyester filaments is poor to inoperable in a dry heat drawing process and the fatigue resistance of the product in rubber is poor.
• a lubricating finish should be applied to the isocyanate-treated polyester filaments prior to drawing.
• hydroxy-containing finishes which are applied from a 5 to 20% solution to give a finish coating of 0.02 to 0.4% on weight of fiber and to apply such finish less than one hour prior to drawing.
• Illustrative of such finishes useful in conjunction with this invention and solvents for forming solutions therefrom are those listed in said copending application.
• the adhesive strength was measured by the "Ring Peel Adhesion" test as follows.
• the drawn polyester filaments, in the form of a cord were dipped in an RFL dip prepared by mixing together 16.6 parts of resorcinol, 14.7 parts of 37% formaldehyde, 1.3 parts of sodium hydroxide, and 332.4 parts of water, aging for 2 hours, then adding 195 parts of a 41% vinylpyridine latex and 50 parts of a styrene-butadiene latex, and aging for an additional 24 hours.
• the RFL dip was cured at 400° F. for 90 seconds.
• the cord was then wrapped in three layers around a 1.625-inch diameter mandrel covered with heavy duty aluminum foil painted with rubber cement.
• a thin sheet of rubber stock was wrapped around the cord-wrapped mandrel and a covering was applied over the rubber stock to stabilize it during curing and to strengthen it for testing.
• the mandrel was placed in an autoclave to cure the rubber at elevated temperature.
• the cured rubber sleeve containing the test cords is cut into 1-inch wide rings which are then removed from the mandrel and placed on an undersized mandrel where they are slit axially through the rubber down to the cord layers but not deep enough to nick or damage the cords.
• the thus prepared "ring" is placed on a free-turning support in an Instron Tester and the loose end of the rubber cover is grasped with a clamp attached to the load cell of the Instron Tester.
• the average tension required to pull the rubber cover from the test cords in a 1-inch wide ring is reported in pounds per inch of width and is averaged for at least four samples.
• fatigue resistance was measured by either the "Disc Fatigue Test” or the “Firestone Compression Fatigue Test”.
• Disc Fatigue Test which is similar to ASTM Method D-885, dipped cord is embedded in rubber to produce a 3 ⁇ 1/2 ⁇ 1/2 inch test sample. The sample is subjected to alternating compression and extension cycles at a rate of 2500 cycles per minute for a period of 24 or 72 hours at ambient temperature. The conditions of test are adjusted to give 12% compression and 6% extension.
• dipped cords are embedded in a 3/4 inch wide rubber strip having a steel wire reinforcing layer.
• the sample is bent over a 1/2 inch diameter rod so the steel wire layer is under tension and the polyester cords are under compression.
• the cords After flexing at a rate of 250 cycles per minute at 160° F. for various periods of time, the cords are stripped from the rubber and the tensile strength determined.
• the fatigue rating is the number of hours required for the cord strength to drop to 20 pounds per cord.
• the stiffness was measured by the "Gurley Stiffness Test" using an instrument sold by W. & L. E. Gurley Co., Troy, N.Y. This test is based on measuring the energy required to bend a "comb-shaped" sample of cords. In a precisely controlled manner, a plurality of 1 inch long cords are laid side-by-side for a 1 inch width and the ends are taped together with 1/2 inch of the cords exposed like teeth in a comb. The sample is placed at the bottom of the path of a calibrated pendulum with the "teeth" extending upwardly. The stiffness of the cords is determined from the distance the pendulum travels after striking the "teeth" of the cord sample.
• Polyethylene terephthalate having a solution IV of 0.88 was melt-spun through a 250-hole spinnerette at a rate of 380 grams per minute.
• the open bundle of filaments was passed over a rotating finish roll ("kiss roll") wetted with a 40% solution of a mixture of aromatic isocyanates containing about 60% methylene-bis(4-phenylisocyanate), about 8% dimerized methylenebis(4-phenylisocyanate) or a total of 68% di-functional aromatic isocyanate, and about 32% polymethylene polyphenyl isocyanate of which 13% was tri-functional and 19% was higher than tri-functional aromatic isocyanate, in monochlorobenzene to give an isocyanate pick-up of 0.3% on weight of fiber.
• the filaments were then wound up as undrawn yarn on tubes. These tube packages of yarn were then transferred to a Dobson and Barlow draw twister where a hydroxy-containing lubricating finish comprising a sulfonated fatty acid-ethylene oxide copolymer, hexadecyl stearate, oleic acid, and a bactericide was applied to the yarn from a 5% solution in a 3:1 mixture of water:acetone from a kiss-roll applicator located between the pre-tension pin and the feed rolls to give a finish pick-up of 0.11% on weight of fiber, and the yarn was drawn to 5.2 times its undrawn length between heated godets across a heated platen to a twister pirn.
• a hydroxy-containing lubricating finish comprising a sulfonated fatty acid-ethylene oxide copolymer, hexadecyl stearate, oleic acid, and a bactericide was applied to the yarn from a
• Example 1 was repeated with various mixtures of aromatic isocyanates, keeping all other conditions the same. The results of the Ring Peel Adhesion test and the Gurley Stiffness Test and the drawability of the various mixtures is reported in Table I.
• Polyethylene terphthalate having a solution IV of 0.88 was melt-spun through a 250-hole spinnerette at a rate of 380 grams per minute.
• the open bundle of filaments was passed over a rotating finish roll ("kiss roll") wetted with a 36% solution of a mixture of aromatic isocyanates containing about 60% methylene-bis(4-phenylisocyanate), about 8% dimerized methylenebis(4-phenylisocyanate) or a total of 68% di-functional aromatic isocyanate, and about 32% polymethylene polyphenyl isocyanate of which 13% was tri-functional and 19% was higher than tri-functional aromatic isocyanate, in monochlorobenzene to give an isocyanate pick-up of 0.3% on weight of fiber.
• a hydroxy-containing lubricating finish comprising a sulfonated fatty-acid-ethylene oxide copolymer, hexadecyl stearate, oleic acid, and a bactericide was applied to the filaments from a 5% solution in a 3:1 mixture of water:acetone from a "shoe" applicator to give a finish pick-up of 0.1% on weight of fiber.
• the filaments were then wound up was undrawn yarn on tubes. These tube packages of yarn were then transferred to a draw twister where the yarn was drawn to 5.2 times its undrawn length between heated godets across a heated platen to a twister pirn.

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• Engineering & Computer Science (AREA)
• Textile Engineering (AREA)
• Chemical & Material Sciences (AREA)
• Chemical Kinetics & Catalysis (AREA)
• General Chemical & Material Sciences (AREA)
• Manufacturing & Machinery (AREA)
• Mechanical Engineering (AREA)
• Treatments For Attaching Organic Compounds To Fibrous Goods (AREA)
• Lining Or Joining Of Plastics Or The Like (AREA)
• Yarns And Mechanical Finishing Of Yarns Or Ropes (AREA)
• Chemical Treatment Of Fibers During Manufacturing Processes (AREA)
• Artificial Filaments (AREA)

Priority Applications (14)

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Publications (1)

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Citations (12)

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• 1972
  • 1972-08-16 US US05/281,248 patent/US4052501A/en not_active Expired - Lifetime
  • 1972-08-16 US US05/281,247 patent/US4052500A/en not_active Expired - Lifetime
• 1973
  • 1973-07-12 AU AU58031/73A patent/AU5803173A/en not_active Expired
  • 1973-07-16 GB GB3381373A patent/GB1409600A/en not_active Expired
  • 1973-07-27 AR AR249302A patent/AR195349A1/es active
  • 1973-08-07 IT IT51891/73A patent/IT990178B/it active
  • 1973-08-13 DE DE19732340876 patent/DE2340876A1/de active Pending
  • 1973-08-14 BE BE134581A patent/BE803612A/fr unknown
  • 1973-08-14 FR FR7329700A patent/FR2196403B1/fr not_active Expired
  • 1973-08-15 DD DD172910A patent/DD110311A5/xx unknown
  • 1973-08-15 NL NL7311255A patent/NL7311255A/xx unknown
  • 1973-08-15 JP JP48091621A patent/JPS49124334A/ja active Pending
  • 1973-08-15 PL PL1973164684A patent/PL89415B1/pl unknown

Patent Citations (12)

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